With hundreds of experiments distilled into three consistent reports, the latest predictions of climate change from the BoM and CSIRO are a reliable source of information.

THE WEATHER IN OUR nation's capital today is predicted to be 28°C. Mostly sunny, with light winds.

I have no crystal ball, but I reckon it's pretty likely that the Bureau of Meteorology is going to be about right. I suppose we'll find out later today.

The Bureau's website is one of the most accessed sites in Australia. Everyone wants to know whether or not to bring a brolly. The fact that it is accessed so often is testament to the fact that the BoM is usually pretty reliable. Sure, we all like to whinge about the weather — particularly when showers show up unexpectedly — but by and large, you've got to admit, they do a pretty good job.

At home, I check the weather before I get up on my phone using the WiFi internet connection I have in the lounge. It's only very recently that WiFi was invented — 1996 — but Aussies are keen on technology and it's really caught on.

WiFi was invented by that other great Australian institution, the CSIRO. It wasn't the first local area network, but it worked the best of the technologies jostling for position back in the day.

Every two years, these two venerable scientific institutions team up to release a State of the Climate report.

Today on what is predicted to be a lovely day in Canberra, BoM and CSIRO scientists will be briefing relevant officials on their findings.

It's the third State of the Climate report from the two and the results are remarkably consistent across time. The first report said that temperatures had increased 0.7°C since 1960; the second stretched out to 1910 and found that temperatures had gone up 0.75°C; the latest suggests it may be 0.9°C since 1910.

The consistent theme here is: hotter.

In fact, in the latest report the BoM and CSIRO scientists took temperature records from 1910 to 2013. They averaged the daily maximums for locations from all around Australia. So Canberra's top of 28 would be averaged with the expected tops of 26 for Sydney, 41 for Meekatharra in outback WA and so on. Then they ranked the average national temperature from hottest to coolest. They then examined how many days each year were in the hottest one per cent of all the days.

The first 30 years, 1910 to 1940, had 28 days that were in the hottest one per cent of all days. Last year, in just one year, there was also 28 days that were in the hottest one per cent.

Given such a shocking increase in the frequency of uncomfortably hot days, the report concludes that "record-breaking summer temperatures in Australia over 2012-2013, are very unlikely to have been caused by natural variability alone."

In order to work out whether the weather is natural variability or could be down to climate change, scientists calculate 'fraction attributable risk'. It's the same mathematics that medical scientists use to work out that smoking increases your risk of lung cancer, or that being overweight increases your risk of diabetes.

The difference with the climate, is that it's just physics. Human beings and medical science have any number of factors that they can't predict. It's the classic tale of someone's grandma who smoked a pack a day and lived until she was 105.

But with climate change, they are only predicting the physical processes that determine weather: water, heat, air movement, molecules, reflection, refraction. Sure it's incredibly complex — we are talking about predicting the behaviour of molecules over the whole planet, after all — but there are fewer wildcards than when dealing with biology.

In theory, it is all predictable, if only you had a computer big enough to handle the information. In practice, there is no computer that big, so they predict with broad brushstrokes the likely future scenarios.

"Warming by 2070, compared to 1980 to 1999, is projected to be 1.0 to 2.5°C for low greenhouse gas emissions and 2.2 to 5.0°C for high emissions," the report notes.

In science, when you want to be right, you do the experiment again. If you get consistent results it puts a tick in the column marked 'probably right'. The best way to show to the world that you're onto something is to repeat the experiment again and again and come up with the same result.

Even better, get a rival scientist to do your experiment and see what their results are. Lots of ticks in the 'probably right' column lends weight to your views.

Scientific papers have detailed instructions on how to run the experiment for this very reason. Scientists want other people to try to replicate their results.

Assessing climate data and making predictions about the future is not rocket science — it's far harder than that. But the consistency of the observations and predictions coming from these two trusted Australian scientific institutions is an indicator of the reliability of the information.

The BoM and CSIRO have consistently returned similar results in hundreds of experiments, which are distilled into these biannual reports.

The very best Australian science gave us WiFi and reliable weather information. The Australian people can be just as confident the climate information from these two organisations is as robust and thorough as the rest of their body of work.

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Comments (12)

Mezaby :

05 Mar 2014 11:36:26am

Well said, Sara. Funny how the BoM and CSIRO have been demeaned by the 'flat earth society' mob who continue to ignore the hard evidence. Lucky they don't imprison scientists these days for exposing the truth like they did in Galileo's time tho. They just ridicule them. How cynical can you get.

John :

12 Mar 2014 7:18:09pm

Please get your facts right, Mezaby.

Galileo was not shown the instruments of torture and told to recant. Galileo was not imprisoned. Those are both constantly repeated myths.

Copernicus lived happily and peacefully in Rome despite his conflict with Catholic theological theory. But he was a compliant and reserved person and was content to work away in private. Galileo, by contrast, was confrontationist and aggressive, and regularly attacked the Universities and science bodies of the time, showing that their teachings were not factual. Because the scientists could not either refute his science or prove their own, they appealed to the Church to have him declared a heretic.

He was not so declared, but the Church insisted that he, like Copernicus, promulgate his work as "theory" and not as "fact", and they required him to live in a villa owned by The Duke of Tuscany. However, they allowed him to carry on his work, set up his laboratory and equipment and travel to and from Rome without hindrance. The Church also provided him with a cook/housekeeper and a personal servant.

Robbie :

David Arthur :

If you couldn't make it to the end of the article, perhaps they should have allocated taxpayer funds to remedial reading? Perhaps you could make it to the end of this:

The sun warms earth with energy, primarily between wavelengths of 0.1 and 4 microns.

Earth dissipates energy to space, primarily between wavelengths of 4 and 40 microns.

Greenhouse gases disrupt transmission of the latter, not the former.

If earth dissipates more energy to space than it receives from the sun, it cools down; if earth dissipates less energy to space than it receives from the sun, it warms up.

Humans have increased and are continuing to increase the atmosphere's greenhouse gas content, which is unavoidably increasingly disruptive of transmission of energy from earth to space. In other words, it is not even possible that global warming isn't occurring.

Ed :

05 Mar 2014 1:34:23pm

Gee March, the fact you couldn't read 800 words says more about your abilities than any editing. If you are not interested in the subject don't read it and please don't use it as an excuse to attack ABC. You sound like one of those barmy tea-party types.

Reinhard :

05 Mar 2014 5:09:05pm

Don't worry March in the name of balance next weeks environment blog. will be written by Amanda Vanstone. She will be telling us how dumping thousands of tonnes of toxic dredge spoil on the Great Barrier Reef will help "adjust" marine sea-grass ecosystems, so there will be no more of those nasty sea turtles, dugongs and dolphins out there causing havoc..

SwampDoktor :

06 Mar 2014 9:19:54am

I'd like to join those thanking the author for the article - it is informative and draws on information from plausible sources. We need to be informed and I certainly respect the integrity of the sources. With such information we can then make up our own mind about the issues, and respond to them, and not attack the author, or the sources, or the medium.

Keith :

08 Mar 2014 2:06:24pm

Yes thanks for you article, one hopes that more is forthcoming, and perhaps with regards to what we are going to do on a daily basis to cope in the extra hot days and extra powerful wind speeds we are to expect. Mind you we might not ever consider putting giant pergola's over our houses to help keep the unrelenting sun off our homes and aid cooling. To quote that big tim bloke on discover downunder "How big is that"

GOrwell :

09 Mar 2014 11:11:28am

I thank my lucky stars every time I see a piece of unbiased reliable reporting of evidence based information such as this. This country will not be served well if institutions such as the BOM, CSIRO and the ABC are allowed to be eroded or damaged.

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About the Editor

Sara Phillips

Sara Phillips has been an environment journalist and editor for eleven years. Learning the trade on environmental trade publications, she went on to be deputy editor of 'Cosmos' magazine and editor of 'G', a green lifestyle magazine. She has won several awards for her work including the 2006 Reuters/IUCN award for excellence in environmental reporting and the 2008 Bell Award for editor of the year.

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